Graphene-based LaF₃ (GN/LaF₃)nanocomposite materials were prepared by the melthod of Liquid-phase Ultrasonic Exfoliation. The morphologies of GN/LaF₃nanocomposite materials were charactered by means of SEM, TEM. Its tribological properties as water additive were investigated using an multi-functional reciprocating friction and wear tester. The lubrication mechanism was discussed based on the results of analysises of SEM, XPS. The results showed that the LaF₃nanoparticles, at the size of 5-50nm, were densely and randomly deposited on the surface of multilayer graphene sheets. The GN/LaF₃nanocomposite materials express good friction-reducing and antiwear performance. Compared with pure water, it can reduce the friction coefficient at 34.35% and the wear mass fall at 52.40% with the load 10N and concentration 0.01wt%. The prosperity is attributed to the effection of the adsorption membrane and tribochemistry reaction films which inhibit the oxidation of Fe and reduce the wear.